Frequently Asked Questions

Bacteriostatic Water for Injection is sterile, nonpyrogenic water containing 0.9% (9 mg/mL) benzyl alcohol as a bacteriostatic preservative, supplied in a multiple-dose vial as a diluent or solvent for compatible drugs that require preparation before injection. It contains no salt or other solute, so it is hypotonic on its own. We stock the factory-sealed 30 mL multi-dose manufacturer presentation, alongside our own-label bacteriostatic water in 10, 20 and 30 mL multiple-dose vials — the own-label vials carry their own labelling (not for injection or infusion), so read the label of the presentation you choose.

Yes. BAC water is simply the common abbreviation for bacteriostatic water — BAC is short for bacteriostatic, nothing more. You may also see it written as bacteriostatic water for injection, BWFI, b/a water or bac water. All refer to sterile water containing 0.9% benzyl alcohol as a bacteriostatic preservative, supplied as a multiple-dose diluent.

Its labelled use is as a diluent: for diluting or dissolving drugs for injection, according to the product information of the medicine being prepared. The preservative is what lets one vial be entered more than once across its in-use period rather than being discarded after a single withdrawal. It has no therapeutic effect of its own, is never injected by itself, and which diluent a medicine takes — and how much — comes from that medicine's product information and a qualified healthcare professional, not from a general page.

Bacteriostatic water (BAC water) contains 0.9% benzyl alcohol as a preservative, which is what allows a sealed multi-dose vial to be entered more than once. Sterile water for injection is preservative-free and its vial is labelled for a single withdrawal — once opened it is used promptly and not re-entered. Both are sterile; both are hypotonic; the preservative is the whole difference, and it is why the two carry different labels and are not interchangeable. Follow the manufacturer product information and your healthcare professional's direction when selecting a diluent.

No. Bacteriostatic 0.9% sodium chloride (bacteriostatic saline) carries the same 0.9% benzyl alcohol preservative and the same multi-dose labelling, but it is a salt solution — isotonic, where bacteriostatic water contains no solute and is hypotonic. Listings often call both “bac water”. A medicine's product information will specify one or the other, and if a listing says “bac water” while the label says “sodium chloride”, the label is what you are buying.

Two dates govern every vial. The printed expiry applies to the sealed vial stored as labelled. From the moment the stopper is first entered, a much shorter in-use period applies — 28 days is the figure commonly stated for benzyl-alcohol-preserved multi-dose presentations, and any figure printed in the product information supplied with your exact vial is the one that governs. Write the date of first entry on the label. Whichever date falls first ends the vial's usable life, and a vial that is cloudy, discoloured or contains visible particles is discarded regardless of either date.

No. Preservative-free sterile water has no bacteriostatic agent, so its label treats it as a single-withdrawal presentation: it is opened, used promptly and not re-entered. If a diluent needs to be drawn from more than once, that is what the bacteriostatic presentations are for — provided the medicine's product information specifies one.

At controlled room temperature — the label states 20 to 25 °C — in the outer carton, away from direct light. It does not need refrigeration and should not be frozen, which can damage the stopper seal. Keep the vial upright with the flip-off cap in place until first use, and inspect it before every entry: it should be clear, colourless and free of visible particles. Any storage, handling or disposal instruction in the manufacturer product information supplied with the vial takes priority.

Benzyl alcohol is a colourless aromatic alcohol used as a preservative in certain injectable solutions. At 0.9% (9 mg/mL) it acts as a bacteriostatic agent — it inhibits the growth of bacteria that might be introduced when a multi-dose vial is entered, rather than killing them outright, and it is not a sterility guarantee. It is also why the label reads “not for use in neonates”: benzyl alcohol has been associated with serious toxicity in newborns, which is the reason preservative-free presentations exist alongside the preserved ones.

No. They are not ready-to-administer medicines. The manufacturer product information warns that intravenous administration of Bacteriostatic Water for Injection or Sterile Water for Injection without a solute may cause haemolysis, because a hypotonic solution damages red blood cells, and that the preserved presentations must not be used in epidural or spinal procedures. Follow the exact label and product information under qualified healthcare-professional direction.

Rarely. A community pharmacy stocks what it dispenses against prescriptions and what its customers buy regularly, and a preserved multi-dose diluent vial is neither — most will not order a single one in for a retail customer, though preservative-free sterile water ampoules are a common pharmacy line. That is why bacteriostatic water in Australia is almost always bought online. We stock the factory-sealed 30 mL manufacturer presentation and dispatch it Australia-wide from Melbourne.

No. We do not require a prescription to order the diluents and consumables we stock; they are sold as labelled, sealed and unopened. What a diluent is used with may itself be a prescription medicine, and everything about that medicine's preparation and use belongs with its prescriber, pharmacist and product information — a diluent order does not change any of that.

Yes. The store is operated by Aus Bac Supply Pty Ltd, an Australian proprietary company, ACN 700 778 614, ABN 96 700 778 614, based in Melbourne and dispatching from Melbourne. The legal operator, contact details, dispatch origin, shipping charges and returns terms are published on the site rather than hidden behind a contact form, and every order is tracked. Support is Mon–Fri, 9am–5pm AEST at hello@ausbacsupply.com or +61 468 034 303. We are an independent retailer: we are not affiliated with, endorsed by or an authorised distributor of any manufacturer whose sealed presentation we supply.

Every manufacturer presentation we supply is factory-sealed in its original packaging, with the manufacturer's own label, lot number and expiry printed on the vial — nothing is relabelled, decanted or repackaged. Check the same things on arrival that you would check from any seller: an intact flip-off cap and stopper, a legible lot and expiry, a clear, colourless solution, and a label that states the benzyl alcohol strength and the vial size. If any of those is wrong, photograph it and contact us before the vial is used.

Standard shipping is $9.99, Express is $14.99, and standard shipping is free on orders over $200, with express $5 on those orders. All amounts are in AUD and include GST where it applies (some items, such as syringes and swabs, are GST-free — the GST in your order is shown at checkout). Orders placed before 1pm Melbourne time on a business day are dispatched the same business day, shipped Australia-wide from Melbourne.

Yes. We ship within Australia from Melbourne and email tracking once your order is dispatched. Standard delivery is typically 2–6 business days depending on the state, and Express is faster in most metro areas. We do not currently ship internationally.

We do not accept change-of-mind returns on sealed sterile products, but your rights under the Australian Consumer Law are not excluded — faulty, damaged or incorrect items are refunded or replaced. See our Shipping & Returns page for full details.

Visa, Mastercard, Amex, Apple Pay, Google Pay, Afterpay, PayID and direct bank transfer. Card payments are processed securely through Stripe with TLS encryption. Card, wallet and Afterpay payments carry a 1.7% + 30c processing fee, shown in the order summary before you pay; PayID and bank transfer have no fee.

Yes — join the Aus BAC Supply members list and we'll email you a one-time $5 code for your first order. Multi-vial packs and bundle kits are also priced below buying the same items separately. We don't publish standing public discount codes, so codes listed on third-party coupon sites aren't ours and won't work at checkout.